A taxonomic revision of the Neotropical genus Cremastosperma (Annonaceae), including five new species

Abstract We present a taxonomic revision of Cremastosperma, a genus of Neotropical Annonaceae occurring in lowland to premontane wet forest, mostly in areas surrounding the Andean mountain chain. We recognise 34 species, describing five as new here: from east of the Andes, C.brachypodum Pirie & Chatrou, sp. nov. and C.dolichopodum Pirie & Maas, sp. nov., endemic to Peru; C.confusum Pirie, sp. nov., from southern Peru and adjacent Bolivia and Brazil; and C.alticola Pirie & Chatrou, sp. nov., at higher elevations in northern Peru and Ecuador; and from west of the Andes, C.osicola Pirie & Chatrou, sp. nov. endemic to Costa Rica, the most northerly distributed species of the genus. We provide an identification key, document diagnostic characters and distributions and provide illustrations and extensive lists of specimens, also presenting the latter in the form of mapping data with embedded links to images available online. Of the 34 species, 22 are regional endemics. On the basis of the extent of occurrence and area of occupancy of species estimated from the distribution data, we designate IUCN threat categries for all species. Fourteen species proved to be endangered (EN) and a further one critically endangered (CR), reflecting their rarity and narrow known distributions.


Introduction
Arguably the most familiar representatives of the largely tropical flowering plant family Annonaceae are those with large, edible fruits, such as species of Annona (Pinto et al. 2005). By contrast, in Cremastosperma R.E.Fr. and most other Annonaceae, the individual carpels that in species of Annona fuse to form syncarpous fruits instead develop into one or more separate monocarps (Van Setten and Koek-Noorman 1992;Chatrou et al. 2004). Whilst Annonaceae can form large canopy trees (e.g. Bocageopsis R.E.Fr., Guatteria Ruiz & Pav.; Hexalobus A.DC., Miliusa Lesch. ex A.DC., Oxandra A.Rich, Xylopia L. (Fries 1959;Mols and Kessler 2003;Maas et al. 2007;Botermans et al. 2011;Maas et al. 2015;Junikka et al. 2016) and can exhibit spectacular floral morphologies (e.g. Monodora Dunal, Uvaria L. ;Couvreur 2009;Gautier and Deroin 2013), species of Cremastosperma are generally somewhat inconspicuous in the field. They are small understorey trees with typical Annonaceae floral morphology (sepals and petals in whorls of three; indefinite numbers of spirally arranged stamens and carpels; Fig. 1a, b, e) bearing a resemblance to various other Neotropical genera with apocarpous, singleseeded, stipitate fruits ( Fig. 2), including the much more abundant, species-rich and widespread Guatteria . The most useful, albeit somewhat obscure, character by which they can be distinguished from these and other similar Neotropical Annonaceae is displayed by the primary vein of the leaves, which is raised on the upper side with an unusual, mostly conspicuous, longitudinal groove (Fig. 3). The individual distributions of the species are restricted to four disjunct areas of lowland to pre-montane tropical forest in South and Central America: the Chocó/Darién/western Ecuador region (the narrow tropical zone to the west of the Andean mountain chain on the Pacific Ocean side of north-western South America) north into Central America; the tropical Andes (including forests on the eastern side of the Andes extending from Colombia through eastern Ecuador and Peru as far south as Bolivia); coastal Venezuela; and French Guiana Pirie et al. 2018;Fig. 4).

Morphology, phylogeny and classification of Cremastosperma
Prior to DNA-based analyses of Annonaceae, various morphological characters were emphasised by different authors in placing Cremastosperma in more or less, formal classifications of Annonaceae. Van Heusden (1992) defined her Cremastosperma group (also including the Neotropical genera Ephedranthus S.Moore, Malmea R.E.Fr., Oxandra, Pseudephedranthus Aristeg., Pseudoxandra R.E.Fr., and Ruizodendron R.E.Fr.) on a combination of floral characters: imbricate, often ciliate sepals and petals; small sepals (rarely over 4 mm long); usually whitish or greenish, sometimes yellowish flowers; and one basal, lateral or apical ovule (Fig. 1g). The broader Malmea group of Walker (1971) also included the Neotropical genera Unonopsis R.E.Fr., Bocageopsis and Onychopetalum R.E.Fr. and the African genus Annickia Setten & Maas. It was characterised by solitary, medium to large, sulcate pollen grains. Group 4 of Van Setten and Koek-Noorman  (1992), defined by transversely grooved or pitted seeds lacking arils, included most of the Cremastosperma group genera of Van Heusden plus a number of Asian taxa (but neither Unonopsis, Bocageopsis and Onychopetalum, nor Annickia). Amongst these taxa, Cremastosperma was noted to be exceptional in the combination of a pitted seed wall (Fig. 2e, f ) with spiniform ruminations -a condition shared with Pseudoxandra and Malmea sensu Chatrou (1998), i.e. not including species formerly included in Malmea which now represent the genera Klarobelia Chatrou, Mosannona Chatrou and Pseudomalmea Chatrou. Molecular phylogenetic studies of Annonaceae using plastid DNA sequence data (Richardson et al. 2004;Mols et al. 2004;Pirie et al. , 2006Couvreur et al. 2011;Chatrou et al. 2012;Guo et al. 2017) have shown strong support for a clade including all the above-mentioned taxa plus various African and a large number of Asian species, classified by Chatrou et al. (2012) under the subfamily Malmeoideae (Fig. 5). Pirie et al. (2006) identified a clade including all Malmeoideae genera with distributions centred in South America (the "SAC clade"; Pirie et al. 2006), which corresponded to the Cremastosperma group of Van Heusden (1992) plus Unonopsis, Bocageopsis and Onychopetalum. This SAC clade was classified formally as tribe Malmeeae by Chatrou et al. (2012) and sister group relationships between Cremastosperma and one or other lineage of (a not demonstrably monophyletic) Pseudoxandra and between the Cremastosperma/Pseudoxandra clade and Malmea were confirmed. The pitted seed wall (Figs. 2 e and f ) and spiniform seed ruminations identified by Van Setten and Koek-Noorman (1992) may thus represent synapomorphies for the Cremastosperma, Pseudoxandra and Malmea clade (Fig. 5).

Taxonomic history of Cremastosperma
The name Cremastosperma was first introduced by Robert E. Fries (1930), based on a species originally described by Diels (1906) under the genus Aberemoa: A. pedunculata Diels (which thus became the type species Cremastosperma pedunculatum (Diels) R.E.Fr.). The name Cremastosperma referred to the position of the ovules, apically attached and pendant within the ovaries (hence "hanging seeds"), as observed by Fries initially in just A. pedunculata (Fries 1930). Fries considered this unusual enough compared to the basally attached ovules of, for example, Malmea and Guatteria to set it aside from other genera and it proved to be largely -though not entirely -consistent in species that he subsequently described under Cremastosperma. Further work by Fries over the subsequent twenty years increased the number of species of Cremastosperma to 17. In 1931, Fries described C. cauliflorum R.E.Fr., C. gracilipes R.E.Fr. and C. megalophyllum R.E.Fr. and made five new combinations transferring species from Cymbopetalum (C. monospermum (Rusby) R.E.Fr.), Guatteria (C. leiophyllum (Diels) R.E.Fr., C. pendulum (Ruiz & Pav.) R.E.Fr., and C. poiteaui (Diels) R.E.Fr.) and Unonopsis (C. polyphlebum (Diels) R.E.Fr.). In 1934, he described four new species: C. longicuspe R.E.Fr., C. peruvianum R.E.Fr., C. guianense R.E.Fr. and C. williamsii R.E.Fr. (Fries, 1934); in 1937 one: C. juruense R.E.Fr. (in which publication he also transferred C. guianense, C. polyphlebum and C. williamsii to the genus Pseudoxandra Fries, 1937); and in 1939, one: C. microcarpum R.E.Fr., plus a variety of C. monospermum: C. monospermum (Rusby) R.E.Fr. var. brachypodum R.E.Fr. (Fries 1939). In the latter paper, he also made a new combination: C. brevipes (DC.) R.E.Fr., under which he brought both names Guatteria brevipes DC. and Cremastosperma poiteaui (Diels) R.E.Fr. into synonymy. In 1948 and 1950, Fries described his last five new species of Cremastosperma: C. anomalum R.E.Fr., C. killipii R.E.Fr. and C. oblongum R.E.Fr., followed by the first species of the genus from the Pacific coast of Colombia: C. novogranatense R.E.Fr. and C. pacificum R.E.Fr. (Fries 1948(Fries , 1950. The death of Fries in 1966(Peterson 1966Buchwald 1970) marked a significant hiatus in taxonomic work on Neotropical Annonaceae in general and work on Cremastosperma was only resumed subsequent to the establishment of the international Annonaceae project 17 years later (Maas 1983). Maas (in Maas et al. 1986) described one species from Panama (C. panamense Maas) and one from Venezuela (C. macrocarpum Maas) and transferred C. anomalum to Malmea. Notably, this latter change removed the single case of a putative Cremastosperma with basally attached ovules; Chatrou (1998) subsequently further transferred it to the newly described Klarobelia, along with a number of more distantly related species formerly placed under Malmea. Pirie and Zapata Cruz (2004) described three species of Cremastosperma from the Marañon basin in northern Peru and Pirie (in Chatrou and Pirie 2005) increased the number of species known from Venezuela from one to two. However, the greatest underestimation of species diversity appeared to be represented by collections from the Chocó/ Darién/western Ecuador region. Although many new collections of Cremastosperma had been made since the final contribution of Fries (Fries 1950), these were predominantly on the Amazonian side of the Andean mountain chain, with far fewer in areas of north-western South America. Nevertheless, the degree of clear morphological differentiation, clear from the previously largely undetermined collections that were available, led Pirie (2005) to describe eight new species from extra-Amazonian Colombia and Ecuador plus Panama. One additional new species, endemic to Amazonian Ecuador, also published in the latter paper, brought the total number of recognised species of Cremastosperma to 31 (including two species, C. killipii and C. juruense, which are synonymised here under C. longicuspe and C. monospermum, respectively). In a precursor to this work, Pirie et al. (2005b) presented informal descriptions of two further putatively new species, for which the material available was at the time deemed insufficient for formal description. Here, we present a fully updated taxonomic revision of the genus including the description of these two plus a further three new species and comprehensive identification keys, plus IUCN preliminary conservation status assessments for all species.
Descriptions follow the form of Pirie et al. (2005b). Measurements are based mostly on dried material. Where measurements are derived from material preserved in alcohol (and dimensions therefore often greater, as the structures are not subject to water loss), these are indicated between square brackets. Unless otherwise indicated, descriptions of the indument of bracts, sepals and petals refer to that on the outer side (the petals generally being rather flat, with the largest surfaces facing in, towards the centre of the flower, or out, away from the centre). According to Chatrou (1998), the inflorescences of all Annonaceae can be considered as terminal: apparently axillary inflorescences in genera such as Guatteria, Klarobelia and Pseudomalmea consist of a short shoot, developing primarily from a leaf-axillary position, subtending a terminal pedicel with flower. The distinction between these two structures is in most (but not all) cases clear, demarcated by an articulation. The short shoot bears a variable number of bracts (referred to here as lower bracts) which in occasional specimens are larger and leaf-like in appearance. The short axillary shoot is described here under the convenient term 'peduncle', following .

IUCN preliminary conservation status
We calculated the extent of occurrence (EOO) and area of occupancy (AOO) per species using ConR (Dauby et al. 2017), using these summaries in addition to the nature of the known distributions of each species to propose preliminary conservation status for all species of Cremastosperma following the IUCN Red List Category Criteria (IUCN 2012). Following IUCN (2012), we adopt a precautionary attitude to applying criteria. Many Cremastosperma species are only infrequently collected and particularly when the only known collections are from a restricted area or considerable time has elapsed since the last collection, we suggest endangered status despite the paucity of data. In general, in the absence of detailed analyses of habitat decline across the wide areas of the distributions of the different species, we assume that decline is ongoing unless it is potentially ameliorated by presence within protected areas (although these are of course not immune from potential threats; e.g. Bass et al. 2010) or where there is evience of local abundance despite a degree of disturbance (e.g. species apparently common in areas close to roads or human habitation).

Data resources
The data underpinning the analyses reported in this paper are deposited at GBIF, the Global Biodiversity Information Facility, https://doi.org/10.15468/41rneo.

Morphological descriptions and taxonomic revision
Thirty-four species are recognised here, of which five (C. alticola Pirie & Chatrou; C. brachypodum Pirie & Chatrou; C. confusum Pirie; C. dolichopodum Pirie & Maas and C. osicola Pirie & Chatrou) are described as new. In most species of Cremastosperma, inflorescences are of single flowers, but in three (C. cauliflorum R.E.Fr.; Fig. 2b, C. napoense Pirie and C. alticola Pirie & Chatrou), a rhipidium is formed by the development of shoots from the axils of bracts on the short axillary shoot. Most flowering collections are in fact in bud, since the mature stage of the flower is relatively brief; mature flowers tend to drop their petals on pressing. Bud shape and development differ between species: bud development can be fully open, giving the appearance of a mature flower (e.g. C. brevipes; C. leiophyllum), loosely open (e.g. C. pedunculatum; C. megalophyllum) or closed; and if closed, buds can be depressed ovoid (e.g. C. pendulum; C. yamayakatense) to broadly ovoid-triangular (e.g. C. monospermum). The presence and type of indument on flowers, fruits and sometimes leaves, is diagnostic for several of the species, e.g. the long golden hairs on all parts of C. bullatum; the dense but shorter indument of C. cauliflorum and C. microcarpum; the unique pattern of indument on the petals of C. awaense; and the lack of indument on many species leading to a characteristic blackish colour of flowers and fruits of dried specimens.
Monocarp shape (i.e. that of the portions of the fruit containing the seeds, as distinct from the stipes on which they are borne) also differs consistently between species, from narrowly ellipsoid (e.g. C. dolichocarpum) through to globose (e.g. C. magdalenae) and from symmetrical to strongly asymmetrical (e.g. C. chococola; C. antioquense).

IUCN prelimanary conservation status
From the extent of occurrence (EOO) and area of occupancy (AOO) of each species estimated using ConR, taking into account presence in protected areas, 10 are classified as Least Concern (LC), six as Near Threatened (NT), three as Vulnerable (VU); fourteen as Endangered (EN) and one (C. brachypodum) as Critically Endangered (CR). Detailed results are presented in Table 1, with discussion of each assessment under the corresponding species treatments.

Discussion
Undescribed diversity, regional endemism and threat of extinction in Cremastosperma species Since the ground-breaking taxonomic work of R.E. Fries (Fries 1930(Fries , 1931(Fries , 1934(Fries , 1937(Fries , 1939(Fries , 1948(Fries , 1950, there have been considerable increases in the numbers of plant collections available for study (ter Steege et al. 2016) and, in recent revisions, numerous previously unknown species of Neotropical Annonaceae have been described. The most extreme example may be that of Pseudoxandra, revised by , in which 80% of species treated were new or very recently described; Klarobelia now comprises 12 species, of which only 3 were described prior to the treatment of Chatrou (1998;i.e. 75% new); and Unonopsis now includes 50 species of which 23 (46%) were described by Maas et al. (2007). The previous state of knowledge of Cremastosperma species diversity was similar: since 1986, we have described 15 new species, which along with the additional five presented here, represents well over half of the 34 now recognised. Notably, the case of the largest Neotropical genus, Guatteria, is somewhat exceptional in this context. Recently revised by Maas et al. (2015), the number of recognised species in fact decreased, with many brought into synonymy. Both phenomena serve to emphasise the importance of performing and using, modern revisionary work: taking Cremastosperma as an example, of the 17 Amazon species documented by Cardoso et al. (2017), one (C. killipii) was placed in synonymy by Pirie, Kankainen and Maas (2005), but adding the new species described here, the total would still rise, to 19.
Of the five Cremastosperma species that we describe as new here, two are endemic to Peru (C. brachypodum and C. dolichopodum) and one is endemic to Costa Rica (C. osicola). Ulloa et al. (2004) reported 236 species of Annonaceae for Peru, of which León and Monsalve (2006) documented 44 endemics, including six species of Cremastosperma. With the newly described species and our updated assessment of species delimitations and distributions, the number of Cremastosperma species native to Peru increases to 17, of which seven are endemic (C. brachypodum, C. cenepense, C. dolichopodum, C. longicuspe, C. pendulum, C. peruvianum and C. yamayakatense). Cremastosperma osicola, the only Cremastosperma found in Costa Rica and the most northerly distributed species of the genus, belongs to the 4.8% of the 454 tree species native to the Osa Peninsula that are found nowhere else (Cornejo et al. 2012). The Osa Peninsula is an important refuge for species with distributions limited to Costa Rica and surrounding regions of Central America (Cornejo et al. 2012), harbouring other Costa Rican endemic Annonaceae, including the recently described Desmopsis verrucipes Chatrou, G.E. Schatz & N. Zamora, Guatteria reinaldii Erkens & Maas, and G. rostrata Erkens & Maas (Erkens et al. 2006).
Across the Neotropics, a similarly high degree of Cremastosperma species endemism is apparent: both species found in Panama (C. panamense and C. westrae) and both in Venezuela (C. macrocarpum and C. venezuelanum) are endemic, as is the one found in French Guiana (C. brevipes). West of the Andes, Colombia houses no fewer than six endemics (C. antioquense, C. chococola, C. dolichocarpum, C. magdalenae, C. novogranatense and C. pacificum) and Ecuador a further one (C. stenophyllum). Despite being more contiguous, the expanses of lowland rainforest found east of the Andes also harbour endemic species in Bolivia (C. leiophyllum) and Ecuador (C. napoense), in addition to those of Peru. Overall, with 22 of 34 species being national endemics and several of the others with similarly restricted distributions, widespread species such as C. monospermum are the exception rather than the rule in the genus. This proportion of species endemism may appear rather high, but is fairly typical for the Neotropics in general and for Neotropical Annonaceae genera in particular. Ulloa Ulloa et al. (2017) presented a recent tally of vascular plant species diversity in the Americas. They documented over 19,000 species for Peru, of which around 40% are endemic. This is more or less the same as the proportion for Cremastosperma species. For Ecuador and Colombia, they documented around 17,500 and 23,000 species, of which 31% and 29%, respectively were endemic. In Cremastosperma, the proportions of endemic species is somewhat lower in Ecuador (two of ten; 20%) and higher in Colombia (6 of 11; 55%), reflecting the greater proportion of more widespread Amazonian species found in Ecuador. Overall regional endemism of other Neotropical Annonaceae genera is similar to that of Cremastosperma, both in other less species rich, Andean-centred clades such as Klarobelia (7 of 12), Malmea (4 of 6), Mosannona (8 of 15) and Pseudomalmea (3 of 4) (Chatrou 1998;Chatrou and Pirie 2005;Erkens et al. 2006); Cymbopetalum Benth. (16 of 27 spp.) and Porcelia Ruiz & Pav. (6 of 8) (Murray 1993);and Trigynaea Schltdl. (5 spp. of 8;Johnson and Murray 1995); and in more species rich and widespread genera such as Duguetia A.St.-Hil. (42 of 93; and Guatteria (92 of 177; Maas et al. 2015).
Particularly for local endemic and rare species, ongoing rates of habitat loss present a severe threat of extinction (IUCN 2012). León and Monsalve (2006) proposed IUCN threat categories for three Peruvian endemic species: C. oblongum and C. peruvianum as vulnerable (VU, B1a: due to restricted and/or fragmented distributions) and C. killipii (= C. longicuspe) as endangered (EN,B1ab(iii): additionally due to decline in area, quality or extent of habitat). In this paper, we present assessments of levels of threat for all of the species of the genus, the majority of these for the first time. The method we employed is based on extent of occurrence (EOO) and area of occupancy (AOO), like that of Johnson and Murray (2018) in their treatment of Africa Xylopia. We also attempt to take into account factors such as trends in habitat loss, although this is based principally on known presence in (at least nominally) protected areas. The results are not entirely consistent with those of León and Monsalve (2006): our assessments for C. longicuspe (VU) and C. oblongum (LC; Table 1) are less severe. However, these species were in need of revision and collections have often been overlooked or misidentified. By contrast, C. peruvianum is morphologically distinctive, apparently genuinely range restricted and also classified as VU according to our results. This suggests that, particularly for the less well known, rarer and more range restricted species (i.e. many of those most likely to be of concern), our assessments should be a useful first estimate. For example, C. peruvianum is one of a number of northern-Peruvian (near) endemics, also including C. bullatum, C. cenepense and C. yamayakatense, for which the threat imposed by narrow distribution is compounded by the lack of protected areas in the region (particularly compared to in adjacent Ecuador; Bass et al. 2010). Overall, the threat assessment results present a picture similar to that reflected in the broad brushstrokes of regional endemism: over half of the species are threatened ( Table 1) and most of those fall under the more severe threat categories as endangered (14) or critically so (1). The total number of collections is shown, including the number georeferenced (thus included in the calculations using ConR). "Unique occurrences" represent those with differing coordinates, whereby for poorly collected species, numbers of collections that could not be precisely georeferenced but nevertheless represent additional occurrences are indicated; "locations" refers to the IUCN definition as "a geographically or ecologically distinct area in which a single threat can rapidly affect all individuals of the taxon present"; and "subpopulations" are "geographically or otherwise distinct groups in the population between which there is little demographic or genetic exchange (IUCN 2012

Phylogeny and biogeography of Cremastosperma
As part of a biogeographic analysis comparing the similar distribution patterns of Cremastosperma and Mosannona species, Pirie et al. (2018) presented a phylogenetic hypothesis for Cremastosperma based on multiple plastid markers. An updated version of that phylogenetic tree, modified to represent names of previously undescribed species, is presented in Fig. 6. The 34 accessions analysed by Pirie et al. (2018) represented 24 of 29 plus two informal species recognised prior to this work. With the taxonomic changes implemented here, this is now 25 of 34 species, of which those from the Pacific coast and Andean valleys of Colombia remain the least well represented.
Within well-supported geographically defined clades, resolution of the plastid phylogeny is limited, with polytomies and low clade support reflecting zero-length or short internal branches (Fig. 6). Plastid markers provided few informative characters at this low taxonomic level and Sanger sequencing approaches are probably not a realistic strategy for deriving fully resolved phylogenies of clades of closely related species in Malmeoideae, which is characterised by low rates of molecular evolution (Richardson et al. 2004;Mols et al. 2004). This also applies to larger genera in the faster evolving Annonoideae, the challenge of Guatteria (Erkens et al. 2007) being a case in point. One alternative currently being explored is to expand plastid datasets using high throughput sequencing (Hoekstra et al. 2017;Lopes et al. 2018). Whole plastid sequences might be expected to deliver a well-resolved plastid gene tree, but particularly at low taxonomic levels, this might differ markedly from the underlying species tree (Doyle 1992;Maddison 1997). The lack of clear monophyly of species, represented by multiple accessions in our analyses, may indicate the influence of population-level processes at recent timescales, which might be frequent in rainforest species due to large effective population sizes maintained over large areas (Pennington and Lavin 2016). Approaches that can target multiple independent nuclear coded markers (e.g. hybrid capture techniques) may be more fruitful and the development of protocols for such markers is of importance to further address problems in species-level analyses in Annonaceae (Couvreur et al. 2018).
Despite these limitations, the current phylogenetic hypothesis (Fig. 6) shows clades restricted to regions to the west and to the east of the Andes and even to regions within Amazonia (Fig. 4). The closely related species of the Northern/lowland Amazonia clade, which appear to have diversified within the region formerly inundated by Lake Pebas (Pirie et al. 2018), includes both hairy (e.g. C. cauliflorum; C. bullatum) and glabrous (C. megalophyllum; C. brachypodum) species and those with both simple (e.g. C. microcarpum; C. gracilipes) and branching (C. cauliflorum) inflorescences. Pollinator-mediated selection for divergent floral traits presents a tempting hypothetical driver for this species radiation, but data on pollinators within the clade is needed to test this. Species of the Southern/montane sister-clade appear more similar one to another, particularly in the common absence of indument, but do include both species with open (C. leiophyllum; C. oblongum) and closed (e.g. C. monospermum; C. yamayakatense) flower bud development. Given the more rugged topography typical of the habitats, particularly of the montane species, shifts in geographic range might have been more important in the speciation process in this clade. Again, more data is needed; in this case on the dispersal vectors of Cremastosperma species, in order to test whether and how dispersal between regions was limited within the timeframe of the species radiation.
The biogeographic scenario inferred by Pirie et al. (2018), on the basis of phylogeny, age estimates and niche modelling, reinforces the importance of the Andean orogeny in creating a barrier to dispersal during the diversification of the clade (Pirie et al. 2006). Further sampling of species of the Pacific coast and Andean valleys might be expected to reveal more ancient divergences, predating the Pliocene/Early Pleistocene rise of the Cordillera Oriental of the northern Andes (Gregory-Wodzicki 2000) or more recent close relationships with other western and Central American species. The strong geographical structure in the phylogeny, as well as the high degree of local species endemism, is consistent with phylogenetically conserved shifts in niche, combined with limited dispersal capability of these understorey trees. Description. Trees or shrubs (0.5-)1.5-20 m tall; young twigs and petioles glabrous to densely covered with appressed or erect, simple, whitish to golden, up to 1 mm long hairs. Leaves distichous, simple, entire, petiolate, exstipulate; lamina elliptic to obovate or narrowly so, index 1.6-5, chartaceous to coriaceous, glabrous (rarely sparsely covered with appressed or erect, simple, up to 1 mm long hairs) above, gla- brous to densely hairy (particularly at the base and on veins) below, base acute, obtuse or rounded, rarely subcordate to cordate, apex acuminate, sometimes caudate, rarely obtuse to acute, extreme tip rounded, venation brochidodromous, primary vein raised over entire leaf length above with an often conspicuous longitudinal groove particularly in the basal half, secondary veins 5-20(-30) on either side of the primary vein, often with 1-6 intersecondary veins, running parallel to primary vein for a short distance, thereafter angles with primary vein either increasing or decreasing towards the apex (or consistent), sometimes branching, often forming distinct loops, smallest distance between loops and margin 1-7 mm, tertiary veins percurrent (or reticulate). Inflorescence of single flowers or occasionally up to 8 in a rhipidium, pendant, clustered in groups of up to 7, terminal on short axillary shoots (i.e. peduncles) on leafy or leafless twigs, older branches or on the main trunk (then often on brachyblasts); 1-several lower bracts, deltate to depressed ovate, rarely narrowly elliptic, leafy, rounded to acute, soon falling off or persistent; single upper bract attached to pedicel, ovate to deltate, acute to obtuse; flower buds open or closed in development, when closed (ovoid to triangular) broadly to depressed ovoid; peduncles, pedicels, outer sides of bracts, sepals and petals glabrous to densely covered with appressed or erect, simple, up to 1 mm long hairs, bracts, sepals and petals ciliate. Flowers actinomorphic, bisexual, with one whorl of free  Chatrou et al. (2018). A putative synapomorphy for the the Malmea, Pseudoxandra and Cremastosperma clade is indicated; one node that is not subject to significant support is indicated with an asterisk. or slightly connate, imbricate, sepals and two whorls of free, imbricate, petals, green, creamy or yellow in vivo, often black in sicco; sepals and petals thin at margins, occasionally with prominent venation; sepals three, much smaller than petals; petals six, the outer ones ovate, elliptic or broadly so, the inner ones elliptic to obovate or narrowly so, stamens numerous (ca. 100), spirally arranged, extrorse, inserted on and below a ventral ridge encircling a central depression in the receptacle in which the carpels are inserted, 1-2 mm long, connective appendage transversely rhombic-hexagonal; carpels 20-40, spirally arranged, free, ovary 1-locular, glabrous or hairy, with 1 basal, lateral or apical ovule (reported by Van Heusden 1992), stigma sessile. Fruit apocarpous, monocarps 5-40, stipitate, mostly asymmetrical, sometimes strongly so, sometimes with an (often excentric) apicule, green maturing mostly through red to brown or black in vivo, light brown to black in sicco. Seeds 1, lateral or apical (reported by Van Setten & Koek-Noorman 1992), ellipsoid to globose, yellow to reddish-brown, surface deeply to shallowly pitted, lacking an aril, with a raised or sunken raphe encircling seed longitudinally (diagonally), regularly (or more sinuously), ruminations spiniform.

Key to Malmea, Pseudoxandra and Cremastosperma
Distribution. 34 species in the Neotropics: from southern Costa Rica in the north to Bolivia in the south. Most species are distributed in regions surrounding the Andean mountain range, two in coastal Venezuela (Cremastosperma macrocarpum Maas and C. venezuelanum Pirie), one in French Guiana (C. brevipes (DC.) R.E.Fr.) and one widespread across Brazil, south of the Amazon River (C. monospermum (Rusby) R.E.Fr.).  Pirie et al. (2018)). A Excluding taxa for which ndhF was unavailable B including all taxa. Topologies and branch lengths are of the best scoring ML trees with scale in substitutions per site. Branch lengths subtending the ingroup are not to scale. Clade support is indicated: ML and parsimony bootstrap percentages (above; left and right, respectively) and Bayesian posterior probabilities (below). Geographically restricted clades/lineages are highlighted with different colours and labelled on the right.
Habitat and ecology. Lowland to premontane tropical wet forest, inundated areas and terra firme. At elevations of 0-2000 m. Flowers and fruit of species of Cremastosperma appear similar in overall morphology and ontology to those of other Annonaceae demonstrated or presumed to be beetle-pollinated and/or bird-dispersed. We have observed in various species that the inner petals form a loose pollination chamber when mature, similar to that observed in, for example, Guatteria (Gottsberger 1970); and flowers of Malmeoideae genera in general are visited at least predominantly by small beetles . Similarly, we have observed in various species that the fruits become fleshy at maturity and often present a colour contrast between, for exam- ple, black monocarps and bright red stipes, representing a classic bird/monkey dispersal syndrome (Gautier-Hion et al. 1985). However, we are unaware of detailed studies of either pollination biology or seed dispersal in species of Cremastosperma.

Key to species of Cremastosperma
Identifying particular species of Cremastosperma with either only flowering or only fruiting material can be challenging. Some species are best distinguished on the basis of fruit characters, others with those of flowers (and only very few can be identified with any confidence on the basis of vegetative characters alone). Unfortunately, collections with both flowers and fruit are the exception rather than the rule. With this key, we attempted to use both flowering and fruiting characters in combination as far as seemed practical, but subsequently pursued separate leads for flowering and fruiting specimens, not all of which will necessarily deliver an unambiguous identification. Some species found in geographically widely disjunct areas can be morphologically rather similar (e.g. C. oblongum in central Peru and C. pacificum from the Pacific coast of Colombia) and others can be rather variable in what usually would be reliable diagnostic characters, such as pedicel, stipe or monocarp lengths (e.g. C. megalophyllum; C. confusum). Where identifications with limited (or potentially ambiguous) material might be uncertain, we list possible species compatible with the leads to that point and would refer the user to individual diagnoses and known distributions.
A number of important diagnostic characters are illustrated in Fig. 7. In a few cases, we make a distinction between acuminate Fig. 7a (e.g. C. microcarpum) and caudate (in the sense of abruptly acuminate; Fig. 7b, e.g. C. gracilipes) leaf apex shapes. This represents an arbitrary, but, the first author believes, nevertheless generally useful, delimitation within a pattern of continuous variation. Nevertheless, there can be considerable variation within species and even within individual plants, which means that this distinction will not necessarily be helpful in every case.

Synoptic Key
Species codes cited refer to those used in the identification list. Those cited under more than one lead are indicated in bold. Where a character state is unknown for a given species, the corresponding code is omitted.
Notes. Branching inflorescences are unusual in the genus, previously described in only two species: C. cauliflorum and C. napoense.
Etymology. The epithet "alticola" refers to the high elevations at which the species has been found, which is unusual for the genus (and also the family in general).
Preliminary conservation status. Neither of the only two known collections of C. alticola was collected in protected areas and one was reported to be found in close proximity to human habitation. Given this low area of occupancy and the likely ongoing decline in area, extent and/or quality of the habitat, we classify the species as Endangered [EN] ( Table 1).
Other  Description. Tree ca. 5 m tall; young twigs and petioles sparsely covered with appressed brown hairs up to 0.2 mm long or glabrous. Leaves: petioles 7-10 by 2-3 mm; lamina elliptic, 16-27 by 6-9.5 cm (index 2.3-2.8), chartaceous, drying to a mosaic of brown and lighter green on both sides, glabrous on both sides, base obtuse, apex acumi-nate (acumen 10-15 mm long), primary vein grooved in the basal half, 1-1.5 mm wide at widest point, secondary veins 8-11, intersecondary veins occasional, distance between from 10 mm at the base to 50 mm closer to the apex, angles with primary vein from 50° at the base to 70° closer to the apex, forming distinct loops, smallest distance between loops and margin 3-4 mm, tertiary veins more or less percurrent. Inflorescence of single flowers, axillary on leafy twigs or from main trunk, then solitary or clustered in groups of at least two on brachyblasts; peduncles ca. 2 by 1.5 mm (in flower), 2-3 by 1.5-2 mm (in fruit); pedicels 20-28 by ca. 1 mm at the base, 1.5-2 mm at the apex (in flower), 20-40 by ca. 2 mm at the base, ca. 3 mm at the apex (in fruit), peduncles and pedicels sparsely covered with appressed whitish-golden hairs to 0.2 mm long; 2 lower bracts, deltate, ca. 1 mm long, obtuse, soon falling off; upper bract attached around halfway along pedicel, deltate, ca. 1 mm long, obtuse, outer side of upper and lower bracts rather densely to densely covered with appressed whitish-golden hairs to 0.2 mm long; closed flower buds not seen; flowers light green, stamens and carpels yellowish or pinkish in vivo, petals dark brown, contrasting to lighter colour of sepals and pedicels in sicco; sepals fused at base, deltate, appressed, 2-2.5 by 2-2.5 mm, acute, soon falling off, sparsely to rather densely covered with appressed whitish-golden hairs to 0.2 mm long; outer petals elliptic, ca. 12 by 8 mm, inner petals elliptic, 10-12 by 5-6 mm, outer side of outer and inner petals rather densely covered with appressed whitish-golden hairs to 0.2 mm long; receptacle depressed ovoid; androecium 5-7 mm diam., stamens ca. 1 mm long, connective appendage 0.5-0.7 mm wide, glabrous; gynoecium 1-1.5 mm diam., carpels ca. 1.5 mm long, glabrous. Monocarps ca. 10, ellipsoid to broadly so, strongly asymmetrical, 13-14 by 11 mm, orange to deep red, maturing to black in vivo, dark reddish-brown in sicco, with an excentric apicule; stipes orange to deep red in vivo, ca. 20 by 1.5 mm; fruiting receptacle depressed ovoid, ca. 6 mm diam; monocarps, stipes and receptacle glabrous. Seeds ellipsoid, reddish-brown with dark pits each surrounded by a raised rim, ca. 12 by 9 mm, raphe sunken, regular.
Notes. The distinctive strongly asymmetrical monocarps of Cremastosperma antioquense could only be confused with those of C. chococola,and collections of both species display cauliflory (though not exclusively so in C. antioquense) with inflorescences inserted on similar brachyblasts. However, C. chococola can easily be distinguished from C. antioquense by its somewhat smaller, narrowly elliptic leaves with typical pinkish-brown colour on the underside (no such colour contrast in the brown/ green-drying leaves of C. antioquense) and by the absence of hairs on the pedicels. The flowers of C. antioquense are superficially similar to those of C. awaense, particularly in the dimensions of the sepals and petals and lengths of the pedicels. However, petals of C. antioquense are uniformly covered in indument in contrast to the distinctive indument patterning on those of C. awaense and the fruits of the two species are more distinct: in contrast to C. awaense, the monocarps of C. antioquense are smaller, shorter than the stipes, strongly asymmetrical and entirely glabrous. In addition, none of the collections of C. awaense display cauliflory, a condition found in both of the two collections of C. antioquense.
Preliminary conservation status. None of the only three known collections of C. antioquense was found in protected areas. Given the low area of occupancy and a likely ongoing decline in area, extent and/or quality of the habitat, we propose to classify the species as Endangered [EN] ( Table 1).

Cremastosperma awaense Pirie
Distribution. Pacific coast of Colombia (Chocó, Nariño) and Ecuador (Carchi, Esmeraldas). Note. Cremastosperma awaense can be distinguished by the unique pattern of indument on the outer sides of the petals; denser at base and in a line leading to the petal apex. The sparse indument of very short (<0.1mm) hairs on the monocarps and stipes are not visible without magnification and the fruits appear glabrous. This character is also exhibited by some specimens of C. westrae. C. awaense can easily be distinguished from both C. westrae and the geographically closer C. stenophyllum Pirie on the basis of the length of the pedicel. The pedicels of C. westrae are shorter (not exceeding 17 mm) and those of C. stenophyllum longer (ca. 45 mm in comparison to 27-28 mm in flower).
Preliminary conservation status. Although the species is distributed across a moderately wide area (EOO >20,000), C. awaense is rather rarely collected (AOO <500 km 2 ) and half of the specimens known to us are from within just one ethnic reserve in Ecuador which reportedly does not confer protected status to the biota. Decline in non-protected areas may lead to a considerable reduction in EOO and hence we assign the category Near Threatened [NT] ( Table 1) ish leaves), from which it differs in the unusually short stipes; further differs from C. monospermum in the shape of the flower bud (depressed ovoid, compared to broadly ovoid-triangular) and from C. monospermum and C. pendulum in the shorter pedicels.
Distribution. Peru (San Martín). Habitat and ecology. Forest. At an elevation of ca. 500 m. Flowering and fruiting: March.
Notes. Cremastosperma brachypodum, known only from the type, is distinctive within Cremastosperma due to the unusual shortness of the stipes, but otherwise typical of species of the southern/montane clade in the absence of indument on all parts.
Etymology. The specific epithet "brachypodum" is derived from the Greek brachy (short) and podum (-stalked), referring to the short stipes.

Cremastosperma brevipes
Distribution. French Guiana, region of Saül and Nouragues. Notes. Cremastosperma brevipes is the only species of the genus found in the Guianas. The leaves, when dried, have a characteristic reddish tinge (particularly on the underside). This species is similar to C. venezuelanum, but differing in particular by the acuminate as opposed to acute or obtuse leaf apex of C. venezuelanum, smaller sepals and monocarps and shorter stipes. Its use as fish bait has been reported. As of many Annonaceae, the bark of C. brevipes has been described as aromatic: on collection of Riera 668, a peppery smell is reported.
Preliminary conservation status. C. brevipes has been collected regularly, occurring over a fairly wide area, including the protected area of Les Nouragues. Least concern [LC] ( Table 1)  Description. Tree 2-10 m tall; young twigs and petioles densely covered with mainly erect golden hairs up to 1 mm long. Leaves: petioles 3-7 mm by 2.5-3 mm; lamina elliptic or narrowly so to slightly obovate, 17-28 by 6-11 cm (index 2.4-3.5), chartaceous, mid-brown, occasionally slightly grey above (immature leaves drying black), sparsely covered with mainly erect golden hairs up to 1 mm long or glabrous above, densely so on edge of lamina and on all veins below, base rounded to subcordate, apex acuminate (acumen 5-20 mm long), primary, secondary and tertiary veins sunken in depressions in leaf surface, primary vein 1.5-2 mm wide at widest point, densely covered with mainly erect golden hairs up to 1 mm long above and below, secondary veins 15-20 (intersecondary veins rare), distance between from 6 mm at the base to 16 mm closer to the apex, angles with primary vein consistently around 60-70°, occasionally branching, forming distinct loops, smallest distance between loops and margin 1-1.5 mm; tertiary veins mostly percurrent. Inflorescences of single, successively produced, flowers, axillary on leafy branches, on leafless branches and produced from the main trunk (then on brachyblasts); peduncles and pedicels sparsely to rather densely covered with mainly erect golden hairs up to 1 mm long, peduncles 17-20 by 1-1.5 mm (in flower), 18-25 by 1.5 mm (in fruit); pedicels up to 120 by 1 mm at the base (in flower), 110-150 by 1.5 mm (in fruit); bracts densely covered with mainly erect golden hairs up to 1 mm long, single lower bract, elliptic to ovate, ca. 2.5 by 1 mm, acute, persistent or falling off; upper bract within central third of pedicel length, elliptic to ovate, 2-3 by 1-2 mm, acute; flower buds depressed ovoid, developing to ovoid before opening; flowers green, maturing to yellow with a basal orange patch on the outside of the outer petals in vivo, golden brown in sicco, outer sides and apical portion of the inner sides of petals and outer sides of sepals densely covered in appressed golden hairs up to 1 mm long, inner sides otherwise glabrous; sepals basally connate, deltate, 5-7 by 6 mm, acute, soon falling off, outer petals broadly ovate, ca. 18 by 15 mm, inner petals ovate, concave, ca. 25 by 12 mm; androecium ca. 5 mm diam., stamens 1-1.5 mm long, connective appendage ca. 0.5 mm wide; gynoecium [ca. 2.5] mm diam., glabrous. Monocarps 8-10, dark brown in sicco, ellipsoid, slightly asymmetrical, ca. 15 by 11 mm, often with an excentric apicule; stipes 14-16 by 1.5 mm; fruiting receptacle 5-6 mm diam., monocarps, stipes and receptacle sparsely to moderately densely covered with erect golden hairs up to 0.2 mm long. Seeds ellipsoid, orange-brown, shallowly pitted, ca.13 by 10 mm, raphe raised, regular.
Notes. Cremastosperma bullatum can easily be distinguished from all other species of Cremastosperma by any one of the number of unique and striking characteristics it displays. The leaf blade has a corrugated (bullate) appearance, both in the field and when pressed, which is due to the deeply sunken nature of the primary, secondary and tertiary venation. The indument present on many of its parts is far longer than in any other species in the genus and, also uniquely in the genus, densely inserted in a halo-like formation around the leaf margin. Other notable characteristics are the unusually long pedicel, the orange colouring of the base of the outer petals of mature flowers, the inner petals considerably longer than the outer petals and the rounded to subcordate shape of the leaf base.
Preliminary conservation status. Cremastosperma bullatum is known from a small number of locations, within a limited area of northern Peru and adjacent Ecuador outside of protected areas. Endangered [EN] ( Table 1) Description. Tree 2-20 m tall, 4-25 cm diam.; young twigs and petioles glabrous to rather densely covered with appressed or erect golden hairs to 0.5 mm long. Leaves: petioles 4-12(-16) by 2-4(-6) mm; lamina elliptic to obovate or narrowly so, (14-)20-61 by 5-14(-22) cm (index 2.3-3.7), chartaceous, olive/brown green above, darker below, glabrous above except for base of primary vein sparsely covered with appressed or erect hairs to 0.3 mm long, base, primary and secondary veins sparsely to rather densely covered with appressed or erect golden hairs to 0.5 mm long below, base acute to obtuse, apex acuminate (acumen 5-45 mm long), primary vein verrucose (particularly at the base), deeply grooved for most of length, 1.5-3.5(-5) mm wide at widest point, secondary veins (6-)10-17, occasionally 1-2 intersecondary veins, distance between from 4 mm at the base to up to 40 mm closer to the apex, angles with primary vein from 45-70° at the base to 45-60° closer to the apex, not branching, forming mostly distinct loops, smallest distance between loops and margin 1-5 mm, tertiary veins percurrent. Inflorescence of 1-5 flowers, branching, solitary or clustered in groups of up to 7, on thick leafless twigs or on main trunk (then often on brachyblasts); peduncles 3-12(-15) by 1-1.5(-3) mm (in flower), 3-15 by 1-3 mm (in fruit); pedicels 10-45 by 1-3 mm at the base (in flower), 15-45 by 1-3 mm (in fruit), peduncles and pedicels rather densely to densely covered with mainly erect golden hairs ca. 0.3 mm long, often with hairs more densely covering the articulation point between shoot and pedicel; single lower bract (from the axil of which short shoots develop bearing new flowers), deltate, 1.5-2 mm long, acute, soon falling off, densely covered with mostly appressed golden hairs to 0.3 mm long; upper bract attached around midway along pedicel, broadly to very broadly ovate or deltate, 2-4 mm long, obtuse or acute, outer side densely covered with appressed or erect golden hairs to 0.3 mm long; closed flower buds depressed ovoid, opening in development; flowers (pale) green, creamy white, greenish-yellow or yellow in vivo, brownish-yellow or brown with orange, dark brown or black base in sicco, outer side of sepals and petals densely covered with erect or appressed golden hairs to 0.4 mm long, inner side of sepals and petals sparsely to rather densely covered with erect hairs to 0.4 mm long or glabrous, base glabrous; sepals free, broadly to very broadly ovate-deltate, mostly recurved, 3-5 by 4-6 mm, obtuse, soon falling off; outer petals elliptic to broadly elliptic, 10-25(-32) by 9-17 mm, inner petals elliptic, 11-21(-32) by 6-11 mm; androecium 7-10 mm diam., stamens 1.5-2 mm long, connective appendage 0.7-1 mm wide; gynoecium 2-3 mm diam., carpels ca. 40, 2-2.3 mm long, sparsely to rather densely covered with mostly appressed golden hairs to 0.2 mm long. Monocarps 9-41, globose to transversely broadly ellipsoid, slightly asymmetrical, 8-13 by 10-14 mm, green maturing to orange, red, brown and black in vivo, blackish-brown or brown in sicco, sometimes with an apicule at or near the apex; stipes 7-23(-32) by 1-2 mm; fruiting receptacle depressed ovoid, 4-11 mm diam; monocarps, stipes and receptacle rather densely covered with erect golden hairs to 0.2 mm long. Seeds broadly ellipsoid to globose, orange, pitted, 9-10 by 9-10 mm, raphe sunken, regular. Notes. Cremastosperma cauliflorum is one of only three species of the genus displaying a branched inflorescence. It can be discerned from C. napoense and C. alticola by the presence of indument on the monocarps and stipes and by the greater length and density of hairs on the inflorescences. The wood is aromatic, flowers reported as vanilla scented.

Cremastosperma cenepense Pirie & Zapata
Distribution. Peru (Amazonas, in the area of the Cenepa River, a tributary of the Marañon River).
Habitat and Ecology. Primary forest. At elevations of 250-400 m. Flowering: not recorded; fruiting: July and August. Vernacular names. Peru: Yais (Amarun; R. Rojas et al. 0255,0269) Notes. Cremastosperma cenepense is most likely to be confused with C. yamayakatense and C. gracilipes, which are more commonly collected in northern Peru and also characterised by relatively small leaves and fruits. It differs in the shape of the leaf base (cordate or subcordate as opposed to acute in C. yamayakatense and C. gracilipes), the indument on the fruits (rather dense as opposed to almost always absent in C. yamayakatense) and lengths of the pedicel (shorter than that of C. gracilipes) and stipes (shorter than those of C. yamayakatense).
Preliminary conservation status. Three of the only four known collections of C. cenepense are from more or less the same locality and none was found in protected areas. Given the low area of occupancy and a likely ongoing decline in area, extent and/or quality of the habitat, we propose to classify the species as Endangered [EN] ( Table 1).
Habitat and Ecology. Tropical wet forest. At elevations of 0-1200 m. Flowering: not recorded; fruiting: January and June.
Notes. The strongly asymmetric monocarps of Cremastosperma chococola resemble those of C. antioquense: see above for distinctions.
Preliminary conservation status. Only three collections of C. chococola are known to us, from different localities but within a restricted region and only one of which is in a protected area. Endangered [EN] ( Table 1).
Other Diagnosis. Cremastosperma confusum is most similar to C. monospermum, which produces effectively indistinguishable small fruits on slender pedicels. C. confusum differs from C. monospermum in the flower buds, which open in development, unlike in C. monospermum in which flower buds remain closed with a characteristic roughly triangular shape. The flowers of C. confusum are more similar to those of C. leiophyllum, from which it differs in the shape and colour of the monocarps, which, unlike those of C. leiophyllum, do not dry black and are not asymmetrical.
Habitat and ecology. Primary and secondary moist and wet forest, occasionally on floodplains. At elevations of 210-670 m. Flowering: August -December; fruiting: January -May, August and October.
Notes. A number of the specimens of Cremastosperma confusum have in the past been identified as C. leiophyllum or C. monospermum, two well known species found relatively nearby in Bolivia and widespread across Bolivia, Brazil and Peru, respectively. The distributions of C. confusum and C. leiophyllum do not overlap, but in the area of Madre de Dios and adjacent La Paz, Bolivia, C. monospermum and C. confusum may both occur and, in this area in particular, non-flowering specimens of the two are often not discernible. These species are closely related as well as morphologically similar and further data to test their boundaries and the potential for gene-flow between species/ populations are warranted. Variation in the size, shape and texture of leaves and length of pedicel of C. confusum is relatively wide, with specimens collected in Cuzco in particular exhibiting larger leaves.
Etymology. The species is named C. confusum because of the past confusion caused by its similarities to different other nearby species and the lack of unambiguous diagnostic characters for the fruiting material.
Habitat and ecology. Forest, at elevations of 1200-1500 m. Flowering: May and December; fruiting: May, July and December.
Notes. Cremastosperma dolichocarpum can be distinguished from other species of Cremastosperma by the unique long-ellipsoid monocarps after which the species is named and identified even when sterile by the conspicuous axillary buds with dense indument.
Distribution. Peru (Pasco). Habitat and ecology. Primary forest remnants. At an elevation of ca. 500 m. Flowering and fruiting: February.
Notes. Cremastosperma dolichopodum is only known from two specimens collected at the same locality, but the length of the pedicel -a generally reliable character within the genus -greatly exceeds that of any similar known species.
Etymology. The epithet "dolichopodum", from the Greek dolicho (long) and podum (-stalked) refers to the unusual length of the pedicel.
Preliminary conservation status. Of the three known collections of Cremastosperma dolichopodum, two are from the same locality, within a protected area, the third from a roadside remnant of primary forest within the same region. Given the extent of collections of other species in the region (with regular documentation of the much earlier described and more widely distributed C. oblongum and C. pendulum) C. dolichopodum must be naturally rare as well of restricted distribution. Endangered [EN] (Table 1) Description. Tree or shrub 0.5-10 m tall; young twigs and petioles glabrous to sparsely covered with appressed brown hairs to 0.4 mm long. Leaves: petioles 2-8 by 1-2.5 mm; lamina elliptic to obovate or narrowly so, 11-28 by 3-10 cm (index 2-4(-4.7)), chartaceous, (pale) greyish-or brownish-green on both sides, often more greyish above, glabrous on both sides, base acute to obtuse or rounded, apex caudate (cusp 10-35 mm long), primary vein lightly grooved for basal third, 1-1.5 mm wide at widest point, more or less verrucose below, secondary veins 8-17, often 1-3 intersecondary veins, distance between from ca. 5 mm at the base to up to 25(-30) mm closer to the apex, angles with primary vein rather variable, from 45-80° at the base to 60-80° closer to the apex, forming distinct loops, smallest distance between loops and margin 2-6.5 mm, tertiary veins percurrent. Inflorescence of single, solitary flowers, on leafy twigs; peduncles 1-4 by ca. 1 mm (in flower), 2-5 by 1.5-2 mm (in fruit); pedicels (12-)15-25 by 1 mm at the base (in flower), 14-30 by 1-1.5 mm (in fruit), peduncles and pedicels rather densely covered with more or less erect brown hairs 0.2 mm long; 2 lower bracts, deltate, ca. 1 mm long, soon falling off, rather densely covered with more or less erect brown hairs 0.2 mm long; upper bract attached around midway along the pedicel, ovate or broadly so, 1-3 by ca. 1 mm, obtuse or acute, outer side sparsely to rather densely covered with appressed or erect whitish hairs to 0.2 mm long; closed flower buds depressed ovoid, opening loosely in development; flowers green to greenish-yellow, pale yellow or cream in vivo, dark brown with a lighter brown calyx in sicco, outer sides of sepals and petals sparsely to rather densely covered with erect or appressed whitish hairs to 0.2 mm long, inner sides glabrous to sparsely covered with appressed whitish hairs to 0.2 mm long (or inner petals papillate); sepals free, broadly ovate to deltate, recurved, 3-4 by 2.5-4 mm, obtuse, soon falling off; outer petals (broadly) elliptic to ovate, 9-15 by 7-12 mm, inner petals elliptic, obovate or narrowly so, 8-16 by 4-7 mm; androecium ca. 5 mm diam., stamens 1.2-1.5 mm long, connective appendage 0.7-0.8 mm wide; gynoecium ca. 2 mm diam., carpels ca. 25, ca. 2.2 mm long, sparsely covered with erect golden hairs 0.1 mm long. Monocarps 3-23, ellipsoid, slightly asymmetrical, 10-15 by 7-9 mm, with an excentric apicule, green maturing to pink or yellow through to red, purple and black in vivo, reddish or dark brown in sicco; stipes green maturing to pink or yellow to red in vivo, 7-17 by 1-1.5 mm, increasing to 3 mm diam. when mature; fruiting receptacle 3-8 mm diam.; monocarps, stipes and receptacle sparsely to rather densely covered with erect whitish hairs 0.1 mm long. Seeds ellipsoid, orange-brown, shallowly pitted, 5-8 by 3.5-6 mm, raphe sunken, regular.
Habitat and ecology. Primary forest, but also secondary, inundated and non-inundated forest. At elevations of 100-500 m. Flowering: January and April -August; fruiting: throughout the year. Notes. Cremastosperma gracilipes most closely resembles C. microcarpum. The hairs on the flowers are shorter and less dense, which results in their drying a darker brown. The leaves are further generally distinctive in the shape of the apex (markedly caudate with an often long drip-tip) and in the green colour they consistently retain on drying. However, none of these characteristics is easy to define objectively or usefully and, although the geographic distributions of the two species are somewhat different (with C. microcarpum extending further into lowland Amazonia), there is apparent overlap. The species are closely related and further data to test their boundaries and the potential for gene-flow between species/populations is warranted. The leaves of C. longicuspe are similar to those of C. gracilipes, but in contrast to C. gracilipes, both flowers and fruit are entirely glabrous.

Cremastosperma leiophyllum
Distribution. Bolivia (Beni, Cochabamba, La Paz, Santa Cruz Notes. Cremastosperma leiophyllum is the most southerly distributed species of the genus and. of the two found in Bolivia, the only endemic. Bud development in C. leiophyllum is open (as opposed to that of C. monospermum). It most closely resembles C. spec B (which is not found in Bolivia), from which it can best be distinguished by the characteristic shape (asymmetrical, the stipes thickening somewhat where they meet the monocarps) and colour (blackish) of the mature fruits when dried. Preliminary conservation status. Although a regional endemic, Cremastosperma leiophyllum has been collected regularly over a faily broad area of Bolivia including two national parks. Least concern [LC] (Table 1) Description. Tree or shrub 1.5-20 m tall; young twigs and petioles sparsely covered with appressed whitish or golden hairs to 0.2 mm long. Leaves: petioles 4-14 by 1-3 mm; lamina elliptic, obovate or narrowly so, 10-27 by 3-11 cm (index 1.5-5), chartaceous, green or greyish-green above, green or brownish-green below, glabrous above, very sparsely covered with appressed whitish hairs to 0.2 mm long particularly on veins below, base acute, rarely obtuse, apex caudate (cusp 20-35 mm long), primary vein 1-2 mm wide at widest point, secondary veins 7-15, intersecondary veins 0-1(-4), distance between from 7-15 mm at the base to 9-18 mm closer to the apex, angles with primary vein from 60-80° at the base to 40-50° closer to the apex, rarely branching, forming distinct loops, smallest distance between loops and margin 2-4 mm, tertiary veins more or less percurrent. Inflorescence of single flowers solitary (or clustered in groups of 2), on leafy twigs; peduncles 2-5 by ca. 1 mm (in flower), 4-10 by 1-2 mm (in fruit), sparsely to rather densely covered with appressed golden hairs to 0.2 mm long; pedicels 10-14 by 1-1.5 mm at the base (in flower), 11-20 by 1-2 mm (in fruit), sparsely covered with appressed golden hairs to 0.2 mm long or glabrous; 2 lower bracts of unequal dimensions, basal lower bract deltate, ca. 0.5 by 0.5 mm, acute, soon falling off, apical lower bract narrowly elliptic, ca. 1.5 by 0.5 mm, rounded, soon falling off, lower bracts sparsely covered with appressed golden hairs to 0.1 mm long or glabrous; upper bract attached near base or midway along pedicel, ovate, ca. 2 by ca. 1 mm, acute, sparsely covered with appressed golden hairs to 0.1 mm long or glabrous; closed flower buds not seen, buds opening loosely in development; flowers yellowish in vivo, brown in sicco; sepals free, deltate, appressed or recurved, 3-4 by 3-4 mm, acute, soon falling off, sepals and petals glabrous; outer petals broadly elliptic, 10-12 by 9-12 mm, inner petals broadly elliptic, ca. 11 by 10 mm; androecium not seen; gynoecium not seen. Monocarps 6-13(-36), ellipsoid, slightly asymmetrical, 12-13 by 8-10 mm, white, red, deep red or deep purple in vivo, reddish-brown to dark brown or black in sicco, with an excentric apicule when unripe; stipes 10-19 by 2 mm; fruiting receptacle 4-5(-9) mm diam.; monocarps, stipes and receptacle glabrous. Seeds ellipsoid, orange or reddish-brown, 8-9 by 5-6 mm, raphe sunken, regular.
Distribution. Ecuador (Napo); Peru (Loreto, San Martín), most collections found in the basin of the Río Huallaga. Notes. Cremastosperma longicuspe most closely resembles C. gracilipes, particularly in the shape of the leaf. However, in contrast to C. gracilipes, the fruits and flowers are glabrous. From the limited material available, the flower buds appear to be loosely, rather than widely open. In describing C. killipii, Fries (1948) noted its similarity to C. longicuspe. The leaves of the type specimen of C. killipii are unusually broad, but leaf and other characters otherwise fall within the variation found in C. longicuspe, including the notable caudate apex.
Preliminary conservation status. Cremastosperma longicuspe is known from a scattering of collections across a reasonably wide area; none within protected areas and with no new collections of the species since September 2000. Given the low AOO and ongoing decline in habitats in the region, it is assigned: Vulnerable [VU] ( Table 1) Fig. 25 Description. Tree 4.5-15 m tall; young twigs and petioles black, verrucose, sparsely to rather densely covered with white-golden appressed hairs ca. 0.4 mm long. Leaves: petioles 10-15 mm long, 2.5-7 mm diam.; lamina narrowly elliptic to elliptic, 35-60 by 10-25 cm (leaf index 2.3-3), chartacous to subcoriacous, olive/dark brown above, lighter below, glabrous above, sparsely covered with white-golden appressed hairs ca. 0.4 mm long on veins below (densely so developing leaves), base acute, apex acuminate (acumen 10-15 mm long), primary vein deeply grooved in basal half, 2-6 mm wide at widest point; secondary veins 10-16, intersecondary veins rare, distance between from 10 mm at the base to 80 mm closer to the apex, angles with primary vein 45° at the base to 60-70° closer to the apex, not branching, forming distinct loops in the apical half to third of the leaf, smallest distance between loops and margin 3-4 mm; tertiary veins mainly percurrent. Inflorescences of single, pendulous flowers, produced from leafless branches; peduncles 5-8 by ca. 1 mm (in flower), ca. 4 by 2 mm (in fruit); pedicels 90 (less mature) -210 by 1 mm at the base, 1.5 at the apex (in flower), ca. 240 by 2 mm at the base, 3 mm at the apex (in fruit); peduncles and pedicels sparsely to rather densely covered with white-golden appressed hairs ca. 0.4 mm long; single lower bract, broadly elliptic, 1-2 by ca. 1 mm, acute, soon falling off, densely covered with whitegolden appressed hairs ca. 0.4 mm long; upper bract attached on lower half of pedicel, elliptic, 1.5-3 by ca. 1 mm, acute, densely covered with white-golden appressed hairs ca. 0.4 mm long; closed flower buds not seen; flowers green (immature) in vivo, medium brown in sicco; sepals free, triangular to broadly trullate, appressed, 3-4.5 mm long, acute, soon falling off, rather densely to densely covered with white-golden appressed hairs ca. 0.4 mm long; outer petals elliptic, ca. 22 by 12 mm, inner petals narrowly elliptic, ca. 22 by 6 mm, sparsely to rather densely covered with white-golden appressed hairs ca. 0.4 mm long; stamens ca. 1.2 mm long, connective appendage ca. 1 mm wide. Monocarps ca. 20, black in sicco, ellipsoid, slightly asymmetrical, ca. 20 by 12 mm, without an apicule; stipes ca. 25 by 2 mm; fruiting receptacle ovoid, 8 mm diam.; monocarps and stipes glabrous, receptacle sparsely covered with white-golden appressed hairs ca. 0.4 mm long. Seeds ellipsoid, 18-20 by 8-9 mm, orange/brown, with many shallow pits, raphe slightly raised, encircling seed longitudinally.
Habitat and ecology. Humid lowland to premontane forest. At elevations of 280-1400 m. Flowering: January and March; fruiting: September.
Notes. Cremastosperma longipes can easily be distinguished from most other species of the genus by the exceptional length of the pedicel, after which the species is named. The flowers and fruits of most species of Cremastosperma are borne on pedicels less than 50 mm long, with rare exceptions such as C. pedunculatum and C. bullatum never exceeding 150 mm in length, significantly shorter than those of C. longipes. The only species with pedicels of a comparable length is the newly described C. dolichopodum, which differs from C. longipes in the lack of indument on the flowers and receptacle. In addition, leaves of C. longipes are unusually large, equalling the maximum dimensions observed in C. megalophyllum, a more densely collected species from Amazonian Colombia, Ecuador and Peru.
Preliminary conservation status. Cremastosperma longipes is only known from three collections from widely spaced localities outside of protected areas. Vulnerable [VU] ( Table 1).
Notes. One of only two species of Cremastosperma found in Venezuela, C. macrocarpum can most easily be distinguished from C. venezuelanum by its smaller leaves (10-30 cm as opposed to 30-53 cm long) and longer pedicels (40-65 mm as opposed to 16-22 mm in fruit).
Distribution. Colombia (Antioquia, west side of the Magdalena valley). Habitat and ecology. Disturbed primary or secondary forest. At elevations of 670-1200 m. Flowering and fruiting: March.
Note. Cremastosperma magdalenae can be distinguished from other species of the genus by the combination of globose monocarps and large sepals which mostly persist into fruiting (one slightly differing collection, Cárdenas 2899, displays immature fuits with smaller sepals only persistent on one of the two duplicates studied). Also noteworthy are the relatively short pedicels and the absence of indument on all parts. The absence of hairs on fruits and flowers reveals the blackish colour typical of specimens of Cremastosperma upon drying. Both C. panamense and C. pacificum (a species found on the Pacific coast of Colombia) also lack indument, but, amongst other differences, the sepals of both species are much smaller and do not persist into fruiting.
Distribution. Amazonian Colombia (Caquetá, Putamayo), Ecuador (Morona-Santiago, Napo, Pastaza, Sucumbíos, Zamora-Chinchipe) and Peru (Amazonas, Loreto). Notes. Despite its name, the size of leaves of Cremastosperma megalophyllum varies from large to relatively small with respect to those of other species of the genus. This variation is also apparent in the size of the fruits, which are similar to those of C. napoense, but which in contrast are never borne on a branching inflorescence. C. megalophyllum is best distinguished by the shape of the glabrous, black-drying flowers: the large sepals open earlier and to a greater extent than the petals (in contrast to those of C. napoense, bud development of which is open from an early stage and the lighter colour (particularly of the pedicel) of which indicates the presence of indument).
Preliminary conservation status. Cremastosperma megalophyllum is one of the more widespread and abundant species of the genus, including occurrences in protected areas in Ecuador. Least concern [LC] ( Table 1). Description. Tree or shrub 2-20 m tall, 2.5-18.5 cm diam.; young twigs and petioles glabrous to rather densely covered with appressed and/or erect white or golden hairs 0.3-0.4 mm long. Leaves: petioles 2-12 by 1.5-3 mm; lamina narrowly elliptic to elliptic or narrowly obovate, 13-31 by 4-12 cm (index 1.8-3.8(-4.8)), chartaceous, green, greyish-or brownish-green or brown on both sides, shiny above, venation below often yellowish, glabrous above, glabrous to rather densely covered with appressed or erect white hairs to 0.2 mm long at the base and on primary and secondary veins below, base acute to obtuse, rarely rounded or narrowly cuneate, apex acuminate (acumen 10-40 mm long), primary vein 1-2 mm wide at widest point, more or less verrucose on both sides, lightly grooved for around half of length, secondary veins 7-15, often 1-4 intersecondary veins, distance between from ca. 5 mm at the base to ca. 20 mm closer to the apex, angles with primary vein mostly from 45-60° at the base to 60-80° closer to the apex, not branching, forming distinct loops, smallest distance between loops and margin 2-7 mm, tertiary veins percurrent. Inflorescence of single flowers, solitary or clustered in groups of up to 3, on leafy or leafless twigs; peduncles (3-)5-15 by ca. 1 mm (in flower), 4-15 by 1-2 mm (in fruit); pedicels (5-)12-24 by ca. 1 mm at the base (in flower), 10-25 by 1-2 mm (in fruit), peduncles and pedicels sparsely to rather densely covered with appressed or erect whitish hairs to 0.3 mm long; 1 to several lower bract(s), the basal-most small and scale-like, those more apical mostly (long) elliptic, occasionally leaf-like, 2-6(-60) by ca. 1 mm, acute, soon falling off, rather densely covered with appressed white hairs to 0.3 mm long; upper bract attached mostly on the basal half of the pedicel, ovate to deltate, 1.5-2.5 by 1-1.5 mm, obtuse or acute, sparsely to rather densely covered with appressed or erect golden hairs to 0.3 mm long; closed flower buds very broadly to depressed ovoid, opening loosely in development; flowers green, maturing to brown, (pale) yellow, cream or white outside, cream or yellow inside, sepals green or dark brown outside, green with a pink base inside in vivo, pale (orange-) brown or brown with dark or reddish-brown base in sicco, sepals and petals rather densely to densely covered with appressed or erect golden hairs (whitish close to the edges) to 0.3 mm long; sepals free or connate for 0.5 mm, broadly ovate to deltate, not reflexed, 3-4[-6] by 2.5-4[-6] mm, obtuse, soon falling off; outer petals ovate to very broadly ovate, rounded, 11-18[-19] by 10-17 mm, inner petals elliptic to (narrowly) obovate, obtuse, 10-16[-22] by 5-8[-10] mm; androecium ca. 7 mm diam., stamens 1.3-1.5 mm long, connective appendage 0.6-0.8 mm wide; gynoecium ca. 1 mm diam., carpels 2-2.5[-2.9] long, sparsely covered with erect whitish hairs to 0.1 mm long. Monocarps (8-)17-33, ellipsoid to broadly ellipsoid, asymmetrical, 8-11 by 6-8 mm, often with an oblique longitudinal groove corresponding to the seed raphe, green maturing to pink or orange through purple or brownish-red, brown and black in vivo, dark or reddish-brown in sicco, with an excentric apicule, monocarps, stipes and receptacle sparsely to rather densely covered with erect whitish hairs ca. 0.1 mm long; stipes 8-16 by 1 mm; fruiting receptacle 4-8 mm diam. Seeds broadly ellipsoid, orange brown, pitted, 6-8 by 5-6 mm, raphe sunken, somewhat irregular. Notes. Cremastosperma microcarpum resembles most closely C. gracilipes, from which it differs in the denser, longer hairs on the flowers and the generally acuminate as opposed to caudate leaf apex (but see discussion under that species). The hairy flower resembles somewhat those of C. cauliflorum, but which cannot be confused as C. microcarpum never exhibits a branching inflorescence. In addition, the monocarps of C. cauliflorum are larger than those of C. microcarpum and characteristically globose to transversely broadly ellipsoid as opposed to ellipsoid.
Notes. Cremastosperma monospermum is the most widespread species of the genusthe only one found both along the eastern foothills of the Andes as far south as Bolivia and across Brazil south of the Amazon. It is best distinguished by the shape of the flower bud: roughly triangular with an obtuse apex, apparently remaining closed throughout development, with the petals not opening fully even at maturity. In most other species of the genus, including the otherwise very similar C. confusum (see notes under that species), the flower bud opens during development. Cremastosperma pendulum and C. yamayakatense also exhibit glabrous, closed flower buds, but the shape of both is depressed ovoid.
The latter also has a short, sturdy pedicel, very different to C. monospermum, the flower of which is borne on a slender and often long (though rather variable) pedicel.
The authors do not consider it useful to recognise sub-specific taxa within C. monospermum. The variation in stipe length and thickness represented by the type of var. brachypodum, described by Fries (1939), falls within that of the species as a whole and is therefore synonymised here.
Notes. The characteristic pattern of indument on the inner petals of Cremastosperma napoense appears to be unique for the genus. The species can be further distinguished by the combination of a branching inflorescence and glabrous fruits. The only other species in the genus with such an inflorescence are C. alticola and C. cauliflorum. Cremastosperma alticola differs in the much shorter stipes and larger monocarps. C. cauliflorum differs both in the presence of brown indument on the (characteristic globose to transversely broadly elliptic) monocarps and in the dense covering of much longer hairs on the flowers.
Distribution. Central and southern Peru (Cuzco, Huánuco, Junín, Loreto, Madre de Dios, Pasco, San Martín and Ucayali) and adjacent Brazil (Acre).  Notes. Cremastosperma oblongum is best discerned from the most similar other species on the basis of floral characters: the sepals are small and recurved (unlike C. megalophyllum) and borne on short pedicels, whilst bud development is open (not the case in C. yamayakatense). A similar species that also occurs in Central Peru is C. dolichopodum, which can be distinguished by the much greater length of the pedicels (both in flower and fruit). Two further undetermined collections from this region (Valenzuela 13205 and Vásquez 35950) are also similar, but differ in the presence of indument on the sepals and receptacles. The leaves of C. oblongum are quite distinctive: rather leathery with a greyish colour on the upper side, with secondary veins forming conspicuous loops and often narrowly elliptic. Fruiting specimens display more variation -particularly in the length of the pedicel. Cauliflorous specimens from the Peruvian department of Pasco (e.g. D.N. Smith 6613 and 6850; Monteagudo et al. 11777) have longer pedicels; the fruits otherwise resemble somewhat those of C. dolichopodum (the pedicels of which are several times longer).
Preliminary conservation status. Cremastosperma oblongum is only found in southern Peru, but within its fairly wide EOO, it is not uncommon, including within protected areas. Least concern [LC] ( Table 1) of the monocarps (ellipsoid, compared to more or less globose in C. panamense); and from all of the above except C. novograntense in the much larger flowers.
Notes. The distribution of Cremastosperma osicola in Costa Rica is the furthest north into Central America of any species of the genus. The species is most similar to C. pacificum, from the Pacific coast of Colombia, from which it can be discerned with flowering material by the much larger flowers (outer petals ca. 31 mm compared to ca. 16 mm in C. pacificum) and with fruiting material by the length of the stipes exceeding that of the monocarps.
Preliminary conservation status. Cremastosperma osicola is known from a small number of populations within a region sufficiently small to qualify it as Endangered, but within a protected area (Golfo Dulce Forest Reserve Description. Tree 3-15 m tall, 2.5-25 cm diam.; young twigs and petioles sparsely to rather densely covered with appressed golden hairs to 0.4 mm long or glabrous. Leaves: petioles 8-16 by 2-4 mm; lamina elliptic to obovate, or narrowly so, 19-41 by 9-16 cm (index 2.1-3.1), chartaceous to slightly coriaceous, brown, brownish-green, or greyish-green and shiny above, brown, pale brown or greenish-brown below, glabrous above, glabrous or sparsely to densely covered with appressed golden hairs to 0.4 mm long particularly on veins below, base acute, apex acuminate (acumen 10-20 mm long), primary vein shallowly grooved at base, 2-3 mm wide at widest point, secondary veins 7-12, intersecondary veins occasionally 1-2, distance between from 8 mm at the base to up to 55 mm closer to the apex, angles with primary vein from 30-50° at the base to 50-70° closer to the apex, not branching, often forming distinct loops for the apical third, smallest distance between loops and margin 1.5-2 mm, tertiary veins percurrent. Inflorescence of single flowers, on leafless twigs; peduncles ca. 1 by 1 mm (in flower), 2-3 by ca. 2 mm (in fruit), rather densely to densely covered with appressed golden or whitish hairs to 0.2 mm long; pedicels 12-20 by ca. 1 mm (in flower), 22-35 by 1.5 mm (in fruit), longitudinally furrowed, glabrous or sparsely to rather densely covered with appressed gold or whitish hairs to 0.2 mm long; single lower bract, deltate, 1-1.5 by 1 mm, obtuse or acute, occasionally persistent, densely covered with appressed gold or whitish hairs 0.2 mm long; upper bract in the lower half of the pedicel, deltate, 1-1.5 by 1-1.5 mm, rounded, outer side sparsely to rather densely covered with appressed gold or whitish hairs to 0.2 mm long or glabrous; closed flower buds not seen; flowers pale greenish-yellow or pale green in vivo, black or dark brown in sicco, sepals and petals glabrous; sepals free, very broadly ovate, 3 by 3-3.5 mm, obtuse, soon falling off; outer petals elliptic to broadly elliptic, ca. 16 by 11-12 mm, inner petals obovate, ca. 15 by 7 mm, obtuse; stamens ca. 1.5 mm long, connective appendage ca. 0.6 mm wide; gynoecium not seen. Monocarps (2-)7-21, ellipsoid, slightly asym- metrical, 15-18 by 10-12 mm, green (immature) in vivo, black or dark brown in sicco, with an excentric apicule, monocarps, stipes and receptacle glabrous; stipes 10-18 by 1 mm; fruiting receptacle depressed ovoid, 3-9 mm diam. Seeds ellipsoid, yellow, furrowed and slightly pitted, ca. 10 by 8 mm, raphe raised within sunken groove, regular.
Habitat and ecology. Tropical wet and pluvial forest, reported as growing on yellow clay with alluvial substrate. At elevations of 5-100 m. Flowering: December and August; fruiting: April and May.
Notes. Cremastosperma pacificum appears similar to a number of other species characterised by the absence of (visible) indument on flowers and fruits, most notably C. magdalenae, C. megalophyllum C. osicola, C. panamense and C. yamayakatense. The sepals of C. magdalenae and C. megalophyllum are much larger (4-7 mm long, as opposed to up to 3 mm in C. pacificum). From the limited floral material available, bud development in C. pacificum would not appear to be open, unlike the fully open bud development of C. osicola and C. panamense and the closed bud shape is similar to that of C. yamayakatense. In contrast to both C. yamayakatense and C. panamense, the monocarps of C. pacificum are relatively large (>15 mm long, as opposed to up to 14 mm). The monocarps of C. pacificum are around the same length as the stipes, as opposed to stipes longer than monocarps in C. osicola.
Habitat and ecology. Premontane and montane primary and secondary forest, sometimes inundated, mainly on soils with calcareous bedrock. At elevations of 850-1800 m (except the single specimen collected in Pastaza (Ecuador) at 360 m). Flowering: July, October-December; fruiting February, July, October and December.
Notes. The pedicels of Cremastosperma pedunculatum are unusually long in the genus, similar to those of C. bullatum (distinguished by the bullate appearance of the leaves and dense, long, indument on most parts) and only exceeded by C. longipes (from the western side of the Andes and with larger leaves) and C. dolichopodum (from further south in Peru). Cremastosperma pedunculatum is otherwise similar to C. alticola, which also occurs at higher elevations in northern Peru and Ecuador (albeit much less frequently collected), differing from C. alticola by the presence of indument on the (longer) pedicels, lack of branching inflorescences and stipes as long as or longer than monocarps.

Notes.
Only three collections of Cremastosperma stenophyllum, one of which is sterile, have been observed by the authors. However, these are consistently distinct from all other species of the genus. C. stenophyllum can be distinguished even when sterile by the narrowly (or nearly so) elliptic long acuminate leaves. The flowers and fruits resemble those of C. awaense Pirie, but both the pedicel and leaf acumen are longer and C. stenophyllum also lacks the distinctive pattern of indument on the petals of C. awaense: the hairs are instead evenly distributed on the outer surface.
Conservation status. We have seen one further specimen since Cremastosperma stenophyllum was described, bringing the total to three, representing highly fragmented populations, none of which is in a protected area. Endangered [EN] ( Table 1).

Preliminary conservation status.
Cremastosperma yamayakatense is restricted in its extent and not found within protected areas. Vulnerable [VU] (Table 1) The type specimen of G. socialis represents a species of Cremastosperma, but to which species it might belong is not clear.